Video streaming over the cellular connection is one of the increasingly popular, as well as demanding, applications on smartphones. In this work, we consider a group of smartphone users, within proximity of each other, who are interested in streaming the same video from the Internet at the same time. The common practice today is that each user downloads the video independently using one connection (e.g., cellular or WiFi), which often leads to poor quality.

We design, implement, and evaluate a novel system, called MicroCast, that cooperatively uses the resources on all smartphones of the group so as to improve the streaming experience. Each phone uses simultaneously two network interfaces: one (cellular) to connect to the video server and another (WiFi) to connect to the rest of the group. Key ingredients of our design include the following. First, we propose a scheduling algorithm, MicroDownload, that decides what parts of the video each phone should download from the server, based on the phones’ download rates and the congestion in the local network. Second, we propose a novel all-to-all local dissemination scheme, MicroNC-P2, for sharing content among group members, which outperforms state-of-the-art peer-to-peer schemes in our setting. MicroNC-P2 is explicitly designed to exploit WiFi overhearing and network coding, based on a local broadcast framework, MicroBroadcast, which we developed specifically for Android phones.

• Demo and poster at the International Workshop on Mobile Computing Systems and Applications 2012 (HotMobile 2012), San Diego, CA, USA, Feb 28-29, 2012.
• Demo and poster at the Information Theory and Applications Workshop 2012 (ITA 2012), San Diego, CA, USA, Feb 5-10, 2012.
• Overview Talk presented at AFOSR Program Review on “Complex Networks”, Washington, DC, Dec. 2011.

• Multi-player Games on Androids: Anh Le, Lorenzo Keller, Christina Fragouli, Athina Markopoulou, “MicroPlay: a Networking Framework for Local Multiplayer Games”, accepted to the 1st SIGCOMM Workshop on Mobile Games (MobiGames), Helsinki, August 2012.

• Video Streaming System built on Androids: L. Keller, A. Le, B. Cici, H. Seferoglu, C. Fragouli, A. Markopoulou, “Microcast: Cooperative Video Streaming on Smartphones,” accepted to MobiSys 2012, Low Wood Bay, Lake District, United Kingdom, Jun 25-29, 2012. (acceptance rate 17.6%) extended abstract)

• Model and NUM Analysis: H. Seferoglu, L. Keller, B. Cici, A. Le, A. Markopoulou, "Cooperative Video Streaming on Smartphones", in Allerton Conference 2010 (invited paper), Sept. 2011, Monticello, IL.

Demo of the whole system: video

Demo of components of the system:

• The value of cooperation and pull vs. push based schemes (by Anh Le, Sept. 2011): video
• The benefits of pseudo-broadcast (by Blerim Cici, Sept. 2011): video
• The value of cooperation (by Lorenzo Keller, Aug. 2011): video.
• Implementing pseudo-broadcast on Android phones (by Blerim Cici, Aug. 2011): video.

• I2NC: H. Seferoglu, A. Markopoulou, K. K. Ramakrishnan, "I2NC: Inter- and Intra- Session Network Coding", in IEEE INFOCOM 2011. Here is a news article featuring this work. And here are the slides.
• All publications on network coding

• Univ. of California, Irvine: Athina Markopoulou, Hulya Seferoglu, Anh Le, Blerim Cici.
• EPFL, Lausanne: Christina Fragouli and Lorenzo Keller.
• And special thanks to Marta Kurant for helping with the videos.

• This work is supported by an AFOSR MURI: "Information Dynamics as Foundation for Network Management" (prime award FA9550-09-0643, subcontract to UCI), by an NSF CAREER grant, and by ArmaSuisse Wissenschaft + Technologie (W+T) Project No. 8003413832.